A double floored construction, i.e., free access floor, has been known. This construction comprises a plurality of floor panels extending above a base floor, such as a concrete floor, so as to establish free space between the base floor and the floor panels for allowing wiring of cables.
With such free access floor, an opening is formed in the floor panel for enabling power cables for an electronic apparatus such as terminal equipment, telephone and/or signal cables to be drawn onto the floor panel surface from the free space below the floor panel or to be drawn into the free space from the surface of the floor panel. The opening is covered by a closure plate mounted thereon. In this connection, reference should be made to Japanese Utility Model Public Disclosure (KOKAI) No. 62-165331.
A prior art closure plate such as shown above is constructed so as to be simply mounted in the opening of the floor panel without any specific interengagement means therebetween and hence is disadvantageous in that the closure plate tends to become loosened and disengaged from the opening when vibration or shock is given to the floor panel or when the cable inserted in the opening is displaced.
It is also necessary for the prior art floor panel that the openings thereof through which no source cable nor signal cable is inserted be covered by a closure plate, while the openings thereof through which source cable or signal cable is inserted be covered by a closure plate having a wiring port formed therein. Accordingly and when an increase in the equipment or modification of the layout, it is required is essential in the prior art floor panel to replace the closure plate previously mounted in the opening with another closure plate of a different type or to form a port in the closure plate by drilling, for example, for suitable application, thus making working the operation very complicated or time-consuming.
Furthermore, the above described prior art floor panel is designed so as to be simply mounted in the opening of the floor panel with the upper surface thereof being flush with the upper surface of the peripheral edge of the opening. It is therefore disadvantageous in that, when an operator intended wants to remove the closure plate from the opening after the completion of installation so as to, for example, draw cables into the free space between the floor panel and base floor, he must have tools, such as screw drivers, in order to wrench the closure plate open with the tip of the driver engaged with the periphery of the closure plate or with the tip of the driver inserted into a hole formed in the closure plate for that purpose.
It is a general object of the invention to provide a closure plate for covering the opening of a floor panel which is capable of being mounted in and removed from the opening of the floor panel with one-touch operation and which is, during attachment to the opening, adapted to be firmly secured to the opening without any looseness therebetween.
It is another object of the invention to provide a closure plate for covering the opening of a floor panel which facilitates increase of equipment and/or modification of the layout of the equipment.
It is further object of the invention to provide a closure plate for covering the opening of a floor panel which can be attached to the opening of a floor panel with one-touch operation without the need of any fixing members, such as screws, and which, in its installed condition, can be easily removed from the opening of a floor panel by hand without the aid of any tools, such as screw drivers.